allow user to control encoding

README.md

@@ -24,8 +24,14 @@ with the up-to-date versions of Python and python-gnupg
 * Python 3
 * [python-gnupg](https://gnupg.readthedocs.io/en/latest/)
 
+# Notes on Scope
+
+Since this script is written to be used as a Sieve filter, no exclusion
+behaviour which is much better achieved with Sieve will be implemented, e.g.
+"do not encrypt emails from kate@gmail.com".
+
 # Credits
 
 * Julian Klode for the [original code](https://github.com/julian-klode/ansible.jak-linux.org/blob/dovecot/roles/mailserver/files/usr/local/lib/dovecot-sieve-filters/gpgmymail)
-* revsuine for some modifications:
-  * Not encrypting already encrypted mail
+* revsuine for modifications to gpgmymail
+

gpgmymail

@@ -39,7 +39,7 @@ import typing
 import gnupg
 
 # constants
-ENCODING='utf-8'  # default is latin-1 which fails w some unicode chars
+DEFAULT_ENCODING='utf-8'  # default is latin-1 which fails w some unicode chars
 
 def is_message_encrypted(message: email.message.Message) -> bool:
     """Determines whether or not an email message is encrypted.
@@ -53,7 +53,8 @@ def encrypt(
         message: email.message.Message,
         recipients: typing.List[str],
         *,
-        unconditionally_encrypt: bool = False
+        unconditionally_encrypt: bool = False,
+        encoding: str = DEFAULT_ENCODING
     ) -> str:
     """Encrypt given message
 
@@ -72,7 +73,7 @@ def encrypt(
         return message.as_string()
     
     gpg = gnupg.GPG()
-    gpg.encoding = ENCODING
+    gpg.encoding = encoding
     encrypted_content = gpg.encrypt(message.as_string(), recipients, armor=True)
     if not encrypted_content:
         raise ValueError(encrypted_content.status)
@@ -108,11 +109,10 @@ def encrypt(
 
     return encmsg.as_string()
 
-def decrypt(message: email.message.Message) -> str:
-    """Decrypt the given message
-    Likely won't work on this server as I don't store private keys"""
+def decrypt(message: email.message.Message, *, encoding: str = DEFAULT_ENCODING) -> str:
+    """Decrypt the given message"""
     gpg = gnupg.GPG()
-    gpg.encoding = ENCODING
+    gpg.encoding = encoding
     return str(gpg.decrypt(message.as_string()))
 
 def main() -> None:
@@ -123,15 +123,18 @@ def main() -> None:
     )
     parser.add_argument('-d', '--decrypt', action="store_true",
                         help="Decrypt rather than encrypt")
+    parser.add_argument('--encoding', action="store", default=DEFAULT_ENCODING,
+                        required=False,
+                        help="Encoding to use for the gnupg.GPG object")
     parser.add_argument('recipient', nargs='*',
-                        help="Key ID or email of keys to encrypt for")
+                        help="Key ID or email of keys to encrypt for")A
     args = parser.parse_args()
     msg = email.message_from_file(sys.stdin)
 
     if args.decrypt:
-        sys.stdout.write(decrypt(msg))
+        sys.stdout.write(decrypt(msg), encoding=args.encoding)
     else:
-        sys.stdout.write(encrypt(msg, args.recipient))
+        sys.stdout.write(encrypt(msg, args.recipient, encoding=args.encoding))
 
 if __name__ == '__main__':
     main()